The invention relates to variable ratio mechanical transmissions and more particularly, to a mechanical transmission having a reduced friction direct drive.
Variable ratio mechanical transmissions are well-known in the prior art. Such transmissions generally have an input shaft from an engine, a clutch housing, a gear train and housing, and an output shaft. A planetary gearing arrangement may be used when it is desired to have the output shaft coaxially aligned with the input shaft. It is known in the prior art to provide for differing input-to-output drive ratios by clamping the ring gear of the planetary gearing arrangement within a fixed gear housing. It is also known to fix the ring gear to the gear housing which is free to turn, with lower ratio drive resulting when the gear housing is clamped, as is shown in U.S. Pat. No. 3,664,471. It will be recognized that for most efficient transfer of power the output shaft should be directly coupled to the input shaft and the gear train should be disengaged to reduce friction. In addition, for driving some devices such as automobiles, a neutral phase is needed wherein the output shaft is disengaged from the input shaft. However, prior art coaxially aligned transmissions have failed to provide a reduced ratio drive, a neutral phase, and a reduced friction direct drive off the input shaft, while maintaining mechanical simplicity and reliability.